Limbo looks and feels like a regular spinning top, but a hidden USB-rechargeable motor on the inside uses a small weight and centrifugal force to keep it running for hours at a time. It doesn’t require a special base (though it comes with one for display purposes), and it doesn’t cheat with magnetic levitation. It’s just physics. Start it running when you get to work, go to lunch when it finally topples, and set it spinning again when you get back.